Real-time clocks (RTCs) are widely used in electronic equipment where the date and time of day or other uses of time and calendar data are critical to the effective use of the equipment. Examples include personal computers and smartphones where the year, month, day, and time of day data are important to the functionality of these devices. In addition, other types of electronic devices utilize RTCs for time and potentially calendar data such as automotive displays, programmable home thermostats, and industrial equipment. Many of these systems require that the RTC continue operation (typically utilizing a battery) while the full system (such as a personal computer or automobile electronics) is either powered off or in a sleep or stand-by mode.